Carson's move is designed to increase the pressure on Shell Oil to clean up soil in Carousel tract. The firm denies health risk.

The city of Carson has declared a local emergency over contamination in a sprawling housing tract, ratcheting up the pressure on Shell Oil to cleanse the neighborhood of the toxic chemicals found in the soil around homes.

City officials hope the declaration will allow them greater authority to order the oil company to complete the cleanup of the site or give them access to federal and state assistance.

For years, residents in the Carousel housing tract have complained about the contamination. They have been advised to limit contact with the soil and not to eat vegetables or fruit grown in their yards.

The City Council's unanimous decision Monday drew raucous applause and cheers from the audience, which included environmental activist Erin Brockovich.

"The city of Carson is in this battle, and we're in the battle to win," Carson Mayor Jim Dear said after the resolution was adopted.

For many residents, it was a watershed moment in the ongoing battle with Shell.

Soil tests revealed elevated levels of benzene and petroleum more than five years ago and residents have complained about a variety of health problems they attribute to the contamination . Shell Oil has stated that state regulatory agencies have concluded there is no imminent health risk.

The Los Angeles Regional Water Quality Control Board, the agency overseeing the process, has ordered Shell to clean up the site, which sits atop a former oil tank farm. But extensive testing of the tract's 285 homes could delay the actual cleanup until 2014.

The resolution called the contamination a "real time emergency safety hazard" requiring "immediate and comprehensive action" and accused the Los Angeles Regional Water Quality Control Board of granting Shell multiple extensions without "meaningful explanation."

The city also said it would request assistance from California Atty. Gen. Kamala Harris and Gov. Jerry Brown.

Kathy Noriega, 43, a homemaker who has lived in the Carousel tract for 23 years, said she worries about the well-being of her children, who are now in college but once played in the dirt in the neighborhood tract.

"You put everything into your home — your hopes, your dreams. That is your future," Noriega said. "Now we don't have that anymore."

Shell officials said Monday that methane gas poses no safety hazard to the neighborhood, despite its high concentrations in the soil, and emphasized that regulators have found "no imminent health risk" in the community.

Shell spokesman Alan Caldwell said the company was "disappointed" by the city's declaration, saying it "will not solve the problem."

"We have always been in favor of expediting the testing and cleanup process as we take the protection of the Carousel residents and the environment seriously," he said.

The Carousel residents and the city are locked in a lawsuit against Shell, in which they blame the soil contamination for a host of illnesses and decreased home values. Dear wants Shell to purchase all of the homes in the tract before proceeding.

"I challenge Shell … to make the people whole financially, and also to relieve the tremendous stress that the residents of Carson in the Carousel tract have been going through," he said.